ABB XT5N400 TMA 400 3P FF

**ABB XT5N400 TMA 400 3P FF** is a **3-pole Tmax XT series molded case circuit breaker** with a **rated current of 400 Amps**. It belongs to ABB's **low-voltage distribution** product line and is primarily used for **protection, control, and isolation** of electrical circuits. It is applied in distribution boxes, control cabinets, and switchboards within industrial and building applications.

Simply put, it is a **400 Amp industrial-grade air circuit breaker**.

### **Model Number Breakdown**
The model number reveals key information:
*   **XT5**: Indicates membership in the ABB **Tmax XT** series of molded case circuit breakers, known for compact design and high performance.
*   **N**: Represents a standard breaking capacity. The specific breaking capacity level requires consulting the manual; typically, the "N" type suits most conventional applications.
*   **400**: Clearly specifies the breaker's **rated current of 400A**.
*   **TMA**: Indicates the breaker is equipped with a **Thermo-Magnetic release unit**.
    *   **Thermal Trip**: Used for **overload protection**, operating on the bimetal principle with an inverse time characteristic (higher current results in shorter trip time).
    *   **Magnetic Trip**: Used for **short-circuit protection**, operating on the electromagnet principle, providing instantaneous action (interrupting high current almost instantly).
*   **400**: Reconfirms the rated current.
*   **3P**: Denotes a **3-pole** breaker.
*   **FF**: Indicates the **terminal type**. **FF** typically stands for **Front Front connection**, meaning all power connections are made from the front side of the breaker. This facilitates easier installation and maintenance, especially in compact switchgear.

### **Key Features & Parameters**
| Feature/Parameter | Description |
| :--- | :--- |
| **Product Series** | ABB Tmax XT Molded Case Circuit Breaker |
| **Number of Poles** | **3P** (Three-pole) |
| **Rated Current (Iu)** | **400 A** |
| **Rated Operational Voltage (Ue)** | Typically up to **690 V AC** |
| **Breaking Capacity (Icu/Ics)** | Determined by the "N" type; consult specific product catalog. For example, at 400V, Icu might reach 50kA or higher. |
| **Release Unit Type** | **TMA - Thermo-Magnetic Release** (Overload and Short-circuit protection) |
| **Mounting Type** | Usually **Fixed Mounting** (Plug-in versions might be available, but FF terminals are typically associated with fixed type). |
| **Terminal Type** | **FF - Front Front Connection** |
| **Standards & Certifications** | Complies with international standards like IEC/EN 60947-2. |

### **Main Functions & Advantages**
1.  **Comprehensive Protection**:
    *   **Overload Protection**: Prevents damage or fire risk to cables and high-current equipment caused by prolonged overcurrent.
    *   **Short-Circuit Protection**: Rapidly interrupts the circuit during severe short-circuit faults, protecting downstream equipment and wiring.
2.  **Control & Isolation**: Can be used for manual switching ON/OFF of the circuit and provides a safe point of electrical isolation during maintenance.
3.  **Compact Design**: The Tmax XT series often has a smaller footprint compared to previous generations for the same current rating, saving panel space.
4.  **High Reliability**: Utilizes quality materials and precision manufacturing to ensure stable operation even in harsh industrial environments.
5.  **Easy Installation**: The front connection (FF) design allows all wiring to be done from the front, eliminating the need for access behind the breaker, significantly simplifying installation and subsequent maintenance.

### **Typical Application Areas**
This high-current molded case circuit breaker is commonly used as a **main switch** or **feeder switch** to protect critical distribution lines and high-power equipment, such as in:
*   **Industrial Plants**: Main power supply protection for production lines, large motor groups.
*   **Commercial Buildings**: Main switch for building floor distribution boards, HVAC units, pump rooms.
*   **Infrastructure**: Power distribution systems in hospitals, data centers, airports.
*   **Energy Sector**: Output protection for solar inverters, wind converter systems.

### **Summary**
The **ABB XT5N400 TMA 400 3P FF** is a reliable and compact high-current molded case circuit breaker. It provides comprehensive overload and short-circuit protection, and its front connection design makes it ideal for space-constrained distribution cabinets. If you need core protection and control for a 400A three-phase line, this circuit breaker is a highly professional and common choice.

**Important Notes**:
*   The selection, installation, and commissioning of circuit breakers must be performed by qualified professional electrical engineers.
*   Choosing the appropriate breaking capacity and release settings requires consideration of specific short-circuit current levels, load types, and coordination requirements.
*   Please refer to the **latest product manuals and technical documentation** from ABB for precise parameters and functionalities.

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